• Energy Research

Isotopic measurements showed that N 2 O production during drought is unexpectedly dominated by denitrification of organic nitrogen.

AbstractDespite its enormous importance for ecosystem services, factors driving microbial recolonization of soils after disturbance are still poorly understood. Here, we compared the microbial recolonization patterns of a disturbed, autoclaved soil using different amounts of the original non-disturbed soil as inoculum. By using this approach, we manipulated microbial biomass, but did not change microbial diversity of the inoculum. We followed the development of a new soil microbiome after reinoculation over a period of 4 weeks using a molecular barcoding approach as well as qPCR. Focus was given on the assessment of bacteria and archaea. We could show that 1 week after inoculation in all inoculated treatments bacterial biomass exceeded the values from the original soil as a consequence of high dissolved organic carbon (DOC) concentrations in the disturbed soil resulting from the disturbance. This high biomass was persistent over the complete experimental period. In line with the high DOC concentrations, in the first 2 weeks of incubation, copiotrophic bacteria dominated the community, which derived from the inoculum used. Only in the disturbed control soils which did not receive a microbial inoculum, recolonization pattern differed. In contrast, archaeal biomass did not recover over the experimental period and recolonization was strongly triggered by amount of inoculated original soil added. Interestingly, the variability between replicates of the same inoculation density decreased with increasing biomass in the inoculum, indicating a deterministic development of soil microbiomes if higher numbers of cells are used for reinoculation.

This perspective paper explores the concept of multispecies design in architecture, focusing on the building scale. Historically, architects have prioritized human needs, neglecting nature’s integration in urban settings, leading to environmental and social challenges. To address these issues, a new multispecies approach that promotes the integration of ecological knowledge into architectural design has evolved. This paper aims to map existing concepts, challenges, and gaps in this novel multispecies approach, focusing on the building scale design process and suggests a roadmap for its implementation. This paper analyzes the existing literature and current architectural practices. This analysis is complemented by the findings from an architectural design studio that have highlighted real-world challenges not readily apparent in the literature. By promoting a multispecies architectural paradigm, this research not only underscores a transformative approach to building design but also positions multispecies design as an essential strategy in combatting the challenges of declining biodiversity and escalating climate change.

Opencast mining for lignite continuously creates areas of land that require restoration. Here we applied a chronosequence approach to investigate the development of soil bacterial communities during 52 years as influenced by the restoration process and subsequent changes in soil physico-chemical conditions starting from the initial reclamation of the sites. By comparison with the unaffected soils near the mine, we were able to address the question if soil bacterial communities have reached a steady state within 52 years, which is comparable to the original soil. Our study revealed three distinct phases of the restoration process, each with a specific bacterial community composition. The effect size of these changes was similar to the one observed for seasonal dynamics at our sites. At the beginning of the restoration process Flavobacteriaceae, Cytophagaceae and Sphingobacteriaceae were found as typical members of the bacterial community as well as Rhizobiales as a result of the cultivation of alfalfa on the restored plots. At later stage the families Peptostreptococcaceae, Desulfurellaceae as well as Streptomycetaceae increased in relative abundance and became dominant members of the bacterial community. Even though overall bacterial abundance and richness exhibited values comparable to the original soil already 5 years after the start of the restoration process, main responder analyses reveal differences in the bacterial community structure even 52 years after the start of the restoration process. Mostly Nitrospirae were reduced in abundance in the soils restored for 52 years compared to the original soils. To broaden the significance of our study, we compared our data bioinformatically with published results from other restored areas, which were previously affected by opencast mining. Despite different durations of the different restoration phase, we could observe a large degree of conformity when bacterial patterns of succession were compared indicating common modes of action of ecological restoration tools for bacterial communities.

Abstract Soil microbial communities regulate global biogeochemical cycles and respond rapidly to changing environmental conditions. However, understanding how soil microbial communities respond to climate change, and how this influences biogeochemical cycles, remains a major challenge. This is especially pertinent in alpine regions where climate change is taking place at double the rate of the global average, with large reductions in snow cover and earlier spring snowmelt expected as a consequence. Here, we show that spring snowmelt triggers an abrupt transition in the composition of soil microbial communities of alpine grassland that is closely linked to shifts in soil microbial functioning and biogeochemical pools and fluxes. Further, by experimentally manipulating snow cover we show that this abrupt seasonal transition in wide-ranging microbial and biogeochemical soil properties is advanced by earlier snowmelt. Preceding winter conditions did not change the processes that take place during snowmelt. Our findings emphasise the importance of seasonal dynamics for soil microbial communities and the biogeochemical cycles that they regulate. Moreover, our findings suggest that earlier spring snowmelt due to climate change will have far reaching consequences for microbial communities and nutrient cycling in these globally widespread alpine ecosystems.

AbstractWarming occurs in the Arctic twice as fast as the global average, which in turn leads to a large enhancement in terpenoid emissions from vegetation. Volatile terpenoids are the main class of biogenic volatile organic compounds (VOCs) that play crucial roles in atmospheric chemistry and climate. However, the biochemical mechanisms behind the temperature‐dependent increase in VOC emissions from subarctic ecosystems are largely unexplored. Using 13CO2‐labeling, we studied the origin of VOCs and the carbon (C) allocation under global warming in the soil–plant–atmosphere system of contrasting subarctic heath tundra vegetation communities characterized by dwarf shrubs of the genera Salix or Betula. The projected temperature rise of the subarctic summer by 5°C was realistically simulated in sophisticated climate chambers. VOC emissions strongly depended on the plant species composition of the heath tundra. Warming caused increased VOC emissions and significant changes in the pattern of volatiles toward more reactive hydrocarbons. The 13C was incorporated to varying degrees in different monoterpene and sesquiterpene isomers. We found that de novo monoterpene biosynthesis contributed to 40%–44% (Salix) and 60%–68% (Betula) of total monoterpene emissions under the current climate, and that warming increased the contribution to 50%–58% (Salix) and 87%–95% (Betula). Analyses of above‐ and belowground 12/13C showed shifts of C allocation in the plant–soil systems and negative effects of warming on C sequestration by lowering net ecosystem exchange of CO2 and increasing C loss as VOCs. This comprehensive analysis provides the scientific basis for mechanistically understanding the processes controlling terpenoid emissions, required for modeling VOC emissions from terrestrial ecosystems and predicting the future chemistry of the arctic atmosphere. By changing the chemical composition and loads of VOCs into the atmosphere, the current data indicate that global warming in the Arctic may have implications for regional and global climate and for the delicate tundra ecosystems.